February 7 ,2005
On Feb. 5, MESSENGER reached an historic point 30.74 million miles (49.47 million kilometers) from Earth. Known as "local max," this point was MESSENGER's farthest distance from home before starting back toward Earth for the gravity-assist flyby on Aug. 2.
The spacecraft "flip" scheduled for March 30 has been moved up to March 8. The flip will turn MESSENGER's sunshade toward the Sun; to this point the spacecraft had been flying with its shade pointed away from the Sun, letting sunlight warm its electronics while providing power to the spacecraft. The decision was made to flip the orbiter sooner when the team saw temperatures rising on the Neutron Spectrometer sensor of the Gamma-Ray and Neutron Spectrometer instrument. "The spacecraft has a large surface area that is collecting a lot of sunlight and at the center is where the Neutron Spectrometer is located," says MESSENGER Mission Systems Engineer James Leary. "An earlier flip will ensure continued, safe operating temperatures for the instrument and spacecraft."
MESSENGER and its systems are in good health and operating normally.
A paper on MESSENGER's innovative phased-array antenna was recently selected as "Best Paper" from the Antenna Measurement Techniques Association (AMTA) 2004 symposium. Titled "Testing of the MESSENGER Phased-Array Antenna" and written by Robert Wallis, Jonathan Bruzzi and Perry Malouf of the Johns Hopkins University Applied Physics Laboratory, the paper is available belolw and will be reprinted in the "AMTA Corner" of an upcoming issue of IEEE Antenna and Propagation Magazine.
Testing of the MESSENGER Phased-Array Antenna (344 KB)
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MESSENGER is the first deep space mission to use an electronically steered phased-array antenna. Two phased arrays, mounted on opposite sides of the spacecraft, provide MESSENGER's high-gain downlink coverage.
Jeopardy Winner: What Is Mercury?
We thought it would take at least one Mercury flyby before the mission would gain pop icon status - but just six months after launch, there was MESSENGER in the final round of the game show Jeopardy! Anne Shivers from Peotone, Illinois, won a semifinal game of the show's 2005 Teen Tournament on Feb. 2 by coming up with the correct question to the Final Jeopardy answer: "Launched in 2004, a spacecraft named MESSENGER is on a mission to study this planet."
MESSENGER is about 91.9 million miles (147.9 million kilometers) from the Sun and 30.7 million miles (49.4 million kilometers) from Earth. At that distance, a signal from Earth reaches the spacecraft in 2 minutes, 45 seconds. The spacecraft is moving around the Sun at 67, 364 miles (108,412 kilometers) per hour. MESSENGER's onboard computers have executed 27,151 commands from mission operators since launch.